Total Synthesis of Zephycarinatines via Photocatalytic Reductive Radical ipso-Cyclization |
| |
Authors: | Haruka Takeuchi Prof. Dr. Shinsuke Inuki Kohei Nakagawa Takaaki Kawabe Dr. Atsuhiko Ichimura Prof. Dr. Shinya Oishi Prof. Dr. Hiroaki Ohno |
| |
Affiliation: | Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, 606-8501 Japan |
| |
Abstract: | We report herein a nonbiomimetic strategy for the total synthesis of the plicamine-type alkaloids zephycarinatines C and D. The key feature of the synthesis is a stereoselective reductive radical ipso-cyclization using visible-light-mediated photoredox catalysis. This cyclization enabled the construction of a 6,6-spirocyclic core structure through the addition of a carbon-centered radical onto the aromatic ring. Biological evaluation of zephycarinatines and their derivatives revealed that the synthetic derivative with a keto group displays moderate inhibitory activity against LPS-induced NO production. This approach could offer future opportunities to expand the chemical diversity of plicamine-type alkaloids as well as providing useful intermediates for their syntheses. |
| |
Keywords: | alkaloids natural products photocatalysis radical ipso-cyclization total synthesis |
|